It long has been recognized that the control of rodents such as rats and mice and similar agricultural pests is highly desirable, since such animals can increase their populations to quickly deplete food supplies meant for humans or other animals. They also spread disease, contaminate the food or directly injure other animals and children. Rats, are extremely cautious of items new in their surroundings consuming strange food in small quantities. Therefore, until the availability of slow acting but lethal toxicant baits, rats were very difficult to poison. The slow acting toxicants are effective because rats apparently cannot connect illness of themselves and others to the food that they are eating until they have consumed a lethal dose. Also, such toxicant bait when eaten makes a rodent thirsty, so that if the rodent is within a structure it will leave in an attempt to find water before drying. This eliminates the problem of odoriferous decay within a structure. However, effective stations must be provided to supply the toxicant bait in an enticing manner without endangering children or larger animals and so that a large number or rodents per bait fill are killed.
To be effective, a bait station must cope with the nature of the pest and the requirements of the toxicant bait. For example, toxicant baits usually require sufficient quantity to provide several days feeding for multiple animals and the station must be large enough to store the bait. Yet rodents have a propensity to get into the bait and excrete upon or otherwise foul it. This makes it unusable for its intended purpose, since later arriving pests may not enter and feed at the fouled bait station. Therefore, the rodents must not be given access to the bait except for feeding.
Mice, generally are inquisitive, but rats hesitate to enter a device which does not provide a visible exit as they enter, and they are most strongly attracted if the visible exit does not disappear as they finally are drawn in by the aroma of the bait to feed. Also the floor of the station should remain dry since most rodents will not enter a wet bait station. Therefore, the station should also be self draining and resistant to wind blown rain if exposed to such conditions.
There is a need therefore, for rodent and similar pesticidal bait stations which provide access and a visible egress for the rodents, and in which the bait containing area is baffled to such a degree that the pest can feed without being able to get into the bait itself. Also, the bait station should be constructed so that entry or access by other than the target pest for whom the station is intended, will be difficult or impossible. It should further be of the nature that the station cannot be entered by children or such that the children cannot reach into the station easily and disturb or obtain the bait. The bait containing portion of the station should be easily recharged and access to the bait recharging area must be locked securely or otherwise closed against the aforesaid children.
Typical patents pertinent to rodent bait stations include Hedrich, et al, Re. No. 14,782; Mayfield, U.S. Pat. No. 2,764,840; Kelly, U.S. Pat. No. 2,944,364; Starr, U.S. Pat. No. 2,977,711; Freeman, U.S. Pat. No. 3,303,600; Anderson, U.S. Pat. No. 3,352,053; Kare, U.S. Pat. No. 3,466,789; Connelly, U.S. Pat. No. 4,182,070; Clark, Sr. U.S. Pat. No. 4,364,194; and Baker, U.S. Pat. No. 4,400,904. The bait station disclosed in Baker has a general "H" configuration so that upon entry to one of the arms of the "H", the rodent can see a way out. However, when the rodent turns down the center arm, its pathway is blocked by the bait container. A visible escape route can not be seen, so the more cautious rats are hesitant about moving to the bait container for feeding. Also, the bait in the Baker station is enclosed in a upstanding tube which provides attraction and leverage for destructive juveniles.